The general object of metrology is to monitor one or more selected physical phenomena to permit a record of monitored events. Such basic purpose of metrology can be applied to a variety of metering devices used in a number of contexts. One broad area of measurement relates, for example, to utility meters. Such role may also specifically include, in such context, the monitoring of the consumption or production of a variety of forms of energy or other commodities, for example, including but not limited to, electricity, water, gas, or oil.
More particularly concerning electricity meters, mechanical forms of registers have been historically used for outputting accumulated electricity consumption data. Such an approach provided a relatively dependable field device, especially for the basic or relatively lower level task of simply monitoring accumulated kilowatt-hour consumption.
The foregoing basic mechanical form of register was typically limited in its mode of output, so that only a very basic or lower level metrology function was achieved. Subsequently, electronic forms of metrology devices began to be introduced, to permit relatively higher levels of monitoring, involving different forms and modes of data.
In the context of electricity meters specifically, for a variety of management and billing purposes, it has become desirable to obtain usage data beyond the basic kilowatt-hour consumption readings available with many electricity meters. For example, additional desired data may include rate of electricity consumption, or may include date and time of consumption (so-called “time of use” data). Solid state devices provided on printed circuit boards, for example, utilizing programmable integrated circuit components, have provided effective tools for implementing many of such higher level monitoring functions desired in the electricity meter context.
In addition to the beneficial introduction of electronic forms of metrology, a variety of electronic registers have been introduced with certain advantages. Still further, other forms of data output have been introduced and are beneficial for certain applications, including wired transmissions, data output via radio frequency transmission, pulse output of data, and telephone line connection via such as modems and/or wireless (such as cellular) linkups.
The advent of such variety and alternatives has often required utility companies to provide data collection mechanisms wherein appropriate data may be collected in environments that are increasingly hostile to such data collection. For example, electrical noise emanating from sources near electricity meter sensing functions may constitute a source of error in collected data. Any such errors may become more troublesome as the complexity of required or desired signal analysis increases.
Electricity meters typically include input circuitry for receiving voltage and current signals or levels at the electrical service. Input circuitry of whatever type or specific design for receiving the electrical service current signals is referred to herein generally as current acquisition circuitry, while input circuitry of whatever type or design for receiving the electrical service voltage signals is referred to herein generally as voltage acquisition circuitry. There are additional issues related to the measurement of voltage and current that present their own problems. One such problem relates to the dynamic range of the measured quantities during operation. Under more or less normal operational conditions, voltage will vary only over a relatively small dynamic range as the voltage range is controlled by the utility supplying the energy. Typically this range is +/−20% of the nominal voltage. For a 120 volt system, a measurement device is thus required to maintain accuracy over a range from 96 to 144 volts or over a dynamic range of 1.5:1.
Measurements of current, on the other hand, present a significantly different problem in that the current can vary widely depending on the loads being operated by the consumer, as well as depending, for example, on the time of day and/or the season of the year. Typical standards require that a measurement device maintain accuracy over a range of between 1.5-200 amps. Such relatively increased dynamic range (calculable in such example to 133:1) for current measurements makes the typical measurement of RMS current much more difficult than the measurement of RMS voltage.
Electricity meter input circuitry may be provided with capabilities of monitoring one or more phases, depending on whether monitoring is to be provided in either a single phase or a multiphase environment. Moreover, it is desirable that selectively configurable circuitry may be provided so as to enable the provision of new or alternative services or processing capabilities within an existing metering device. Such variations in desired monitoring environments or capabilities, however, lead to the requirement that a number of different metrology configurations be devised to accommodate the number of phases required or desired to be monitored or to provide alternative or additional processing capability within a utility meter.
As such, it is desired to provide a metrology technology that permits the collection of accurate data regardless of the environment in which the metrology device is installed and load under which the supply source operates, i.e., to provide a metrology device which is universally applicable with respect to environment.
While various aspects and alternative embodiments may be known in the field of utility metering, no one design has emerged that generally encompasses the above-referenced characteristics and other desirable features associated with utility metering technology as herein presented.
Various disclosures concern designs relating to signal noise reduction, including the following patents and articles: U.S. Pat. No. 6,498,820 B1 entitled Low Complexity Frequency Estimator And Interference Cancellation Method And Device by Thomson et al.; U.S. Pat. No. 6,330,275 B1 entitled Method And Apparatus For Overcoming Periodic Disturbances In Digital Subscriber Loops by Bremer; U.S. Pat. No. 6,018,364 entitled Correlated Double Sampling Method And Apparatus by Mangelsdorf; U.S. Pat. No. 5,966,684 entitled Method And Apparatus For Cancelling (sic) Periodic Electrical Interference by Richardson et al.; U.S. Pat. No. 4,885,722 entitled Method For Removing Low-Frequency Noise From Records With Data Impulse by Leland; “Numerical-Integration Techniques Speed Dual-Slope A/D Conversion,” Grandbois et al., Microchip AN788, © 2002 Microchip Technology, Inc.; and “Improvement of Spectral Resolution in the Presence of Periodic Noise and Microphonics for Hyper Germanium Detector Gamma-Ray Spectrometry Using a New Digital Filter,” Schultz et al., ORTEC, Advanced Measurement Technology, Inc. Sep. 29, 2004.
The disclosures of the foregoing United States Patents and publications are for all purposes hereby fully incorporated into this application by reference thereto.
While various implementations of metrology devices have been developed and various noise filtering techniques have been developed, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the subject technology.